@article{UZERU_2002_3_a1,
     author = {L. G. Tonoyan},
     title = {On the some extremal problem},
     journal = {Proceedings of the Yerevan State University. Physical and mathematical sciences},
     pages = {7--11},
     year = {2002},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZERU_2002_3_a1/}
}